Acoustic sensors over one-third of the nation's capital reportedly are on gunfire surveillance that is helping police identify possible crime scenes in violence-plagued neighborhoods within a matter of minutes.

About 39,000 separate incidents of gunfire have been documented by ShotSpotter's web of at least 300 acoustic sensors across 20 square miles of the city, The Washington Post reported.

A gift of $2 million in federal grant money enabled the District of Columbia to first install ShotSpotter sensors eight years ago, and the district has since invested another $3.5 million toward maintaining the crime-fighting tool, The Post reported.

"It is a valuable tool that provides almost instantaneous alerts that allow officers to be dispatched quicker for the sound of gunshots," Police Chief Cathy L. Lanier wrote in a statement to The Post. "It has also been instrumental in determining crime trends and establishing information in investigations."

When a noise is picked up, one or more of the sensors analyzes audio of the sound, and, if it is determined to be a gunshot, police are notified in about 40 seconds, the newspaper said.
The audio sensors are able to make sense of where the shot originated from, and software can pinpoint the exact location within only a few feet at times.

Lydia Barrett, a spokeswoman for ShotSpotter, told the Miami Herald that the company signs a contractual agreement with law enforcement clients assuring them the system will pick up 80 percent of gunshots in an outdoor coverage area.

"But in nearly all of our cities, the number is significantly higher than that," she said. Some U.S. towns have opted for similar surveillance devices, including "smart" lampposts that illuminate streets and walkways while also providing authorities with an extra set of eyes and ears on civilians.

Acoustic sensors over one-third of the nation's capital reportedly are on gunfire surveillance that is helping police identify possible crime scenes in violence-plagued neighborhoods within a matter of minutes.